Sound-transmitting apparatus.



M. E. PEARSON.

SOUND TRANSMITTING APPARATUS. APPLIOATIOHIILED JAN. 20, 1913, nmwnwzn FEB. 691915.

1,134,059, Patented Mar.30,1915.

- WITNESSES: INVENTOR v ATTORNEY ting A MILES E. PEARSON, 0F SEATTLE,

WASHINGTON ASSIGNOR, BY MESNE ASSIGNMENTS,

T0 UNIVERSAL HIGH-POWER TELEPHONE COMPANY, OF SEATTLE, WASHINGTON,

A CORPORATION OF WASHINGTON.

SOUNDTRANSMITTING APPARATUS.

Specification of Letters Patent.

Patented Mar. 30, 1915.

Application filed January 20, 1918, Serial No. 7433,00? Renewed February 6, 1915. Serial No. 6,669.

-To all whom it may concern:

Be it known that 1, MILES E. PEARSON, a citizen of the United States, residing at Seattle, in the county of King and State of \Vashington, have invented certain new and useful Improvements in Sound-Transmitparatus, of which the following is a speci cation. 1

This invention relates to sound amplifiers or repeaters; and is designed more especially for use on telephone systems whereby the 'messages transmitted thereupon are ren-- dered with greater volumeand loudness an without impairing clearnessor articulation of the produced sounds.

The invention consists inthe novel arrangement and adaptation of devices, as

will be hereinafter described and claimed.

The accompanying drawing is a side View partly in section and partly in elevation of devices embodying the present. invention.

The reference numerals-1 indicate receptacles arranged in axial alinement with each other. Secured to the opposing walls of resistance chambers 2 afforded by the respective receptacles are, plates3 and 4 which serve as outwardly and inwardly positioned electrodes for circuit wires 3 and 4 Intermediate the plates of each chamber isa' disk 5 which is carried upon the end of a rod 6 which passesthrough a guide 7 formed of insulating material and has its other end secured to a resilient element, such, for-example, as-spring 8. These springs, as illustrated, are connected at their ends to screw threaded pins 9 extending through frame 1' members 10 for engagement with adjusting screws 11 whereby the tension or resiliency of the springs may be regulated.

Secured to the respective springs are the armatures 12 for the cores. 13 of thespools 14 of electro-magnets provided upon permanent magnets 15 which, in the illustration,

are shown as horse shoe magnets. These magnets are rigidly secured to a suitable support such as a .post 16 securedto the frame members 10.

.Granules of carbon or an equivalent material, indicated by 17 are provided in the chambers 2 at opposite sides of the disks 5. These disks afford the electrodes of power connections comprising rods 6 and wires 18 which are connected with a sourceof direct current electric supply such as a battery 19.

The windings of the magnet spools 14 are electrically connected with each other by a wire 20 and by wires 21 with the secondary winding of induction coils 22 whose primary winding is in the primary or transmitting circuit '23 and 24: represents a battery provided in the last named circuit.

Joined with the wires 3 aud t, are the terminals of the primary of induction'coils 26 Whose secondary coil is connected by wires 27 with a receiver 28.

In the foregoing description of details of the various instrumentalities employed, it will be seen that, broadly, the system consists of a transmitter circuit and a receivirg circuit inter-related by electro-magnetically operated resistance devices. The transi'uitter circuit, generally speaking, consists of the electro-magnets 14 which are in the secondary side of the induction coil 22. The receiver circuit includes the resistance devices formed by the stationary electrodes 3 and 4:, movable electrodes 5 and granular media 17 which devices are connected, as

described, with the source of "current 19 and the induction coil 26 of the receiver.

The transmitter circuit operates through the electro-magnets 14 on the said resistance devices by the vibration of the'armatures 12 due to an undulatory' current traversing the current traversing the secondary winding when a person speaks into the transmitv ter 24 Obviously, as a rising 'current impulse traverses electro-magnet's 14, the armatures 12' would be'attracted toward the pole-pieces of the magnets and during a declining impulse traversing the electro-magnets the springs 8 operate to retract the armature from the magnets andin this manner a re ciprocatory movement is imparted to the movable electrode 5, first compressing the granular material between electrodes 4 and 5 on one stroke and then compressing the granular material between electrodes 3 and 5 on the reverse stroke. This vibratory or reciprocatory movement of the movable electrodes takes place with strict conformity with the oscillatory movement of the diaphragm in the transmitter 24 and the effect isthat current impulses of varying strength are generated in the receiver circuit by reason of the resistance devices. formedby' the I trodes, electrode magnets operating on the 'armatures in-cooperation with the springs fixed and movable electrodes and granular material between them. Y

Sounds impressed on the diaphragm of the transmitter 24 will be reproduced at the receiver 28 at a' greatly amplified'and "a maximum clearness.

Having descr m; i 11- 1,:

A device of the class described comprising a .pair. of supports, springs extending between-said supports, an armature upon each ofSaid-springs, aresistance varying device for each armature vdisposed. between said supports .and including outer. and, inner sta-.

' tionary electrodes and anintermediate granular mass between each pair ofelectrodes, a movable electrode .within, each .of'. said ibed my invention, What 1" granular mas ses, rods" -rigidly connecting said armatures and said movable elecfor imparting noveinen'tto the movable electrodes, a transmitter circuit for said electrode magnets; a battery and an induction coil in said circuit, separate circuit v vires each connecting an outer and an inner-one of said-stationary. elec rodeand a re e v nc cuit in the electrical connection with each of said circuit wires and an induction coil in said. receiver circuit.

Signed at Seattle, Wash, this 11th day'oi January, 1913 v MILES E. PEARSON,

Witnesses:

. Pmmm BARNES, E. PETERsoN. 

